The popularity of WiFi has increased dramatically over recent years. This trend is set to continue. As shown in FIG. 8, different signals appear in the WiFi bands, including Bluetooth signals, Zigbee, microwave oven signals, etc. The presence of these signals may cause inter-system interference and reduce the spectrum usage efficiency. To facilitate an increase in data bandwidth that is inevitably associated with increased use, it is important to increase spectrum usage efficiency. Accurate signal and interference identification in WiFi bands is important as a fundamental driver for achieving this aim. Fading channel condition makes accurately distinguishing between signals and noise very challenging.